Your gut and bones might seem to have little in common, but the gut is “command central” for many functions, including nutrient absorption and immune health. In fact, 70% of your immune system is in your gut.
Bacteria that live in your gut and make up your gut microbiome also produce vitamins, including thiamine, folate, biotin, riboflavin, pantothenic acid, and vitamin K, a vitamin important for healthy blood clotting. So, your gut microbiome contributes to your nutritional status.
Scientists also believe a healthy gut may support healthy bones, but how? Osteoporosis is a condition where bones become thinner, weaker, and more prone to breaking. Bone density decreases, and the risk of breaking (fracture) a bone rises. The term osteoporosis literally means “porous bone.” So porous is bone with osteoporosis that minor trauma from sneezing or coughing can cause a fracture.
Osteoporosis results from a reduction in bone mass and changes to bone tissue that make bones more brittle and likely to fracture. Bone loss is one reason people become frail and prone to bone breaks. When they fall and break a large bone, like the hip bone, it’s hard to recover. Studies show that fracturing a hip doubles the risk of mortality over a 12-year period after the fracture.
How Gut Health Affects Bone Density
Could a healthy gut lower your risk of bone loss and osteoporosis? Scientists now know that the bugs that live in your gut produce metabolites that affect bone metabolism, the breakdown, and the building of new bone tissue. Studies show that people with osteoporosis have a gut microbiome that differs markedly from those with healthy bones. It’s an intriguing finding, but there could be another factor that explains the link between the gut microbiome and bone health. Let’s take a closer look at the link between your gut and your bones.
Calcium Absorption and the Gut Microbiome
Beyond producing metabolites that affect bone build-up and breakdown, gut bacteria influence the absorption of nutrients that affect bone health, including calcium, a key mineral involved in bone health. Certain gut bacteria that are part of a healthy gut microbiome boost calcium absorption from the gut and help ensure your bones have access to the calcium they need. So, a healthy gut microbiome may help your bones get more calcium.
When you consume certain types of fiber, gut bacteria produce short-chain fatty acids. Not only do these fatty acids have an anti-inflammatory effect on the intestines, but they also lower the pH (acid-base balance) in the intestinal tract, and that enhances calcium absorption.
There’s also evidence that certain short-chain fatty acids boost the activity of osteoblasts, cells that produce new bone. They also reduce the activity of osteoclasts, cells that break down bone. The result is a net production of new bone. That’s what you want for a healthy skeleton.
What does this show? Feeding your gut fiber, a dietary component that most people don’t get enough of, may boost short-chain fatty acid production and enhance the absorption of bone-building calcium. Plus, it may have a direct effect on new bone production through its effect on osteoblasts.
The Benefits of Prebiotic Fiber
The type of fiber that boosts short-chain fatty acid production in the gut is prebiotic fiber, but not all fiber is prebiotic. Excellent sources of prebiotic fiber include:
- Garlic
- Dandelion greens
- Chicory
- Onions
- Leeks
- Jerusalem artichokes
- Bananas
- Wheat bran
- Oats
- Konjac
- Seaweed
- Cocoa powder
- Barley
- Asparagus
- Jicama root
- Ground flaxseed
Getting more of these foods is beneficial for your gut microbiome and helps boost your fiber intake too. Fiber is an essential part of a healthy diet. Doctors and nutritionists recommend men get at least 38 grams of fiber daily and women 25 grams of fiber per day. Unfortunately, most people don’t get enough of it, and the daily intake in North America is about half or even less than that. By adding prebiotic-rich fiber to your diet, you also help your body avoid a fiber shortfall.
Add prebiotic-rich foods slowly to your diet. If you introduce them too quickly, you could experience gas and bloating. The best time to introduce prebiotic-rich fiber for bone health benefits is during adolescence and the teen years when bone building is at its peak. However, there’s evidence that prebiotics also enhances bone health even as an adult.
Plus, there are other health benefits of consuming prebiotic fiber. Short-chain fatty acid production in response to prebiotic fiber reduces inflammation in the gut and helps keep the lining of your colon healthy. It’s healthy food for your gut bacteria too!
What about Probiotics for Bone Health?
Prebiotic refers to fiber that supports healthy gut bacteria, while probiotics are gut-friendly bacteria that directly support gut health. You can get probiotics by eating fermented foods, like fermented vegetables, yogurt with active cultures, and kefir.
Are probiotics effective for building bone density? One randomized clinical study found that bone density improved in response to kefir, and consuming kefir was linked with enhanced healing of wrist fractures. One strain of bacteria called Lactobacillus reuteri appears to be effective at preventing bone loss. One mechanism may be increased production of short-chain fatty acids by this strain of bacteria. Now you know why. Short-chain fatty acids boost the activity of bone-building osteoblasts.
The Bottom Line
Keeping your gut microbiome healthy has many benefits. Along with a diet that includes adequate nutrition and exercise, adding more prebiotic fiber and fermented foods to your diet may give you an edge for keeping your bones healthy.
References:
Zhang J, Lu Y, Wang Y, Ren X, Han J. The impact of the intestinal microbiome on bone health. Intractable Rare Dis Res. 2018;7(3):148-155. doi:10.5582/irdr.2018.01055.
McCabe L, Britton RA, Parameswaran N. Prebiotic and Probiotic Regulation of Bone Health: Role of the Intestine and its Microbiome. Curr Osteoporos Rep. 2015 Dec;13(6):363-71. doi: 10.1007/s11914-015-0292-x. PMID: 26419466; PMCID: PMC4623939.
“Prebiotics | Osteoporosis-Studies.” osteoporosis-studies.com/category/supplements/prebiotics/.
Whisner CM, Weaver CM. Prebiotics and Bone. Adv Exp Med Biol. 2017;1033:201-224. doi: 10.1007/978-3-319-66653-2_10. PMID: 29101657.
Whisner CM, Weaver CM. Prebiotics and Bone. Adv Exp Med Biol. 2017;1033:201-224. doi: 10.1007/978-3-319-66653-2_10. PMID: 29101657.
Calcif Tissue Int (2018) 102:443–479.
“Are Probiotics a Therapy for Osteoporosis, Bone Loss and ….” 11 Nov. 2018, https://melioguide.com/osteoporosis-nutrition/probiotics-bone-loss/.
“FastStats – Osteoporosis.” 14 Apr. 2021, https://www.cdc.gov/nchs/fastats/osteoporosis.htm.
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